1. Field of the Invention
The present invention relates to a method used in a wireless communication system and related communication device, and more particularly, to a method of handling resource allocation for a machine type communication (MTC) and related communication device.
2. Description of the Prior Art
A long-term evolution (LTE) system supporting the 3GPP Rel-8 standard and/or the 3GPP Rel-9 standard are developed by the 3rd Generation Partnership Project (3GPP) as a successor of a universal mobile telecommunications system (UMTS), for further enhancing performance of the UMTS to satisfy increasing needs of users. The LTE system includes a new radio interface and a new radio network architecture that provides a high data rate, low latency, packet optimization, and improved system capacity and coverage. In the LTE system, a radio access network known as an evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNBs) for communicating with multiple UEs, and communicating with a core network including a mobility management entity (MME), a serving gateway, etc., for Non-Access Stratum (NAS) control.
A LTE-advanced (LTE-A) system, as its name implies, is an evolution of the LTE system. The LTE-A system targets faster switching between power states, improves performance at the coverage edge of an eNB, and includes advanced techniques, such as carrier aggregation (CA), coordinated multipoint transmission/reception (CoMP), uplink (UL) multiple-input multiple-output (MIMO), etc. For a UE and an eNB to communicate with each other in the LTE-A system, the UE and the eNB must support standards developed for the LTE-A system, such as the 3GPP Rel-10 standard or later versions.
A machine type communication (MTC) device which can automatically perform predefined jobs and report corresponding results to other devices, a server, a NB or an eNB can be used in various areas, such as security, tracking and tracing, payment, healthcare, metering, etc. Further, the MTC device preferably reports the corresponding results via a wireless link such that limitation caused by environment can be removed. However, the wireless link used by the MTC device is needed to be established, and radio resource required by the wireless link is needed to be allocated (i.e., assigned). Reuse of existing infrastructures and wireless communication systems become a viable choose for operation of the MTC device. Therefore, the UMTS, the LTE system and the LTE-A system, etc., developed by the 3GPP which are widely deployed are suitable for the operation of the MTC device.
However, a number of MTC devices deployed within a geographic area maybe very large for most situations (e.g., metering, security, etc.). That is, an eNB may need to manage (e.g., control, communicate with) thousands to tens of thousands of MTC devices at the same time. In such situations, the eNB which usually manage hundreds of UEs may not be able to manage such large number of MTC devices. For example, a larger number of MTC devices may perform a random access (RA) procedure for communicating with the eNB at the same time. And RA related signalings of different MTC devices may collide with each other such that only a few MTC devices can perform the RA procedure successfully. Thus, large amount of resources may be wasted for performing the RA procedure repeatedly. Thus, resource allocation for the MTC devices becomes a severe problem for existing wireless communication systems, and is a topic to be discussed and addressed.